I guess you need to install sensors for measuring these variables (there's a lot of possibilities), but, likely, these information already exist close to your study area. Where is it?
Remote sensing is difficult to be used at microscale, even though you can try.
For satellite soil moisture products, here is a list (with sensor, frequency, spatial sampling, temporal resolution, and data period) of products freely available (microwave band, coarse resolution):
ESA-CCI, C-X-band, ~25 km, 1-day, 1979-2013
TMI, C-band, ~25 km, 1-day, 1998-now
AMSR-E, C-band, ~25 km, 1-day, 2002-2011
ASCAT, C-band, ~12 km, 1-day, 2007-now
SMOS, L-band, ~50 km, 3-day, 2010-now
AMSR2, C-band, ~25 km, 1-day, 2012-now
SMAP, L-band, ~36 km, 2-day, 2014-now
No high resolution (e.g., 100 m-1 km) product is available so far, in the near future a soil moisture product from Sentinel-1 will be available. Moreover, a 1 km downscaled soil moisture product integrating SMOS and MODIS data should be available soon.
For other meteorological data, you can check for data availability from ground networks, or again you can consider satellite products for rainfall and evapotranspiration.